** New Features in MacTeX-2018 and TeX Live 2018 **

MacTeX-2018

Applications/TeX

MacTeX-2018 installs the typesetting portions of the distribution in /usr/local/texlive/2018, a location rarely seen by users. The graphical interface programs needed to access TeX are installed in /Applications/TeX.
This location has been simplified this year for easier use. The four GUI programs BibDesk, LaTeXiT, TeX Live Utility, and TeXShop are at the top level, and a small number of documents and spelling programs are in a folder named Docs and Spell Utilities.

If users installed other programs in /Applications/TeX, they will remain, of course. Old documents installed in /Applications/TeX by MacTeX will be removed because they now live in the Docs and Spell Utilities folder.
But the Excalibur spell checker is a special case. It used to live in /Applications/TeX/Excalibur, but is now installed in Docs and Spell Utilities. Some users installed extra dictionaries in the old /Applications/TeX/Excalibur. If such dictionaries are found, then the old folder will also remain and users can leave it alone or merge it into the new folder as desired.

The four GUI programs we install are TeX Live Utility, a program to update and maintain TeX Live, BibDesk, a program to create reference databases, LaTeXiT, a program to create mathematical formulas to be dragged into applications like KeyNote and Pages, and TeXShop, a front end to TeX and LaTeX. New users should open the folder Docs and Spell Utilities and read the short document READ ME FIRST. This document explains how to create and typeset a short document using TeXShop, and then lists many ways to learn more about TeX and begin serious work.

Many front ends are available on the Macintosh for TeX. Some are commercial and some are free. A number of free alternatives are available in the MacTextras portion of MacTeX.

TeX Live Utility and tlmgr

In 2017, the TeX Live infrastructure and in particular the command line program tlmgr (TeX Live Manager) were extensively revised for added security. This support was provided by the encryption program PGP (Pretty
Good Privacy), and more specifically the open source version of this program Gnupg, abbreviated gpg. This program is
often provided on Linux systems, but is not part of Mac OS.

Because some countries have legal restrictions on encryption software, gpg is not provided by TeX Live. Tlmgr will operate without security
enhancements if gpg is absent.

Most Macintosh users don't directly access tlmgr, but instead use it indirectly through TeX Live Utility, which is installed in /Applications/TeX. TeX Live Utility
has been upgraded to support the new tlmgr. When it first runs after TeX Live 2018 is installed, it displays a dialog titled ``Enable security validation of packages.".
If the user clicks "Enable," gpg is downloaded from a third party site and installed inside TeX Live.

TeX Live Utility and the TeX Dist Pref Pane

Previously, MacTeX installed a preference pane for Apple's System Preferences allowing users to select the active TeX distribution. Unfortunately, this Preference Pane was a plugin for System Preferences, and when Apple changed System Preferences, the Preference
Pane needed to be recoded. Apple often made changes.

In 2017, the functionality of the Preference Pane was moved to TeX Live Utility and the Preference Pane is no
longer provided. To see a list of TeX distributions on your machine, run TeX Live Utility and select the item "Change Default TeX Live Version"
from the Configure menu. A list of distributions will appear. Select the distribution you want to activate.

MacTeX does not remove old Preference Panes. To remove the pane, go to /Library/PreferencePanes and move
TeXDistPrefPane.prefPane to the trash.

Many users know that /Library/TeX/texbin is a symbolic link to the binaries of the active distribution, replacing /usr/texbin in older
systems. However, neither link is
changed by TeX Live Utility or the Preference Pane when switching distributions. So please avoid the temptation to "do the job yourself by rewriting /Library/TeX/texbin."

Miscellaneous

MacTeX installs the full version of TeX Live, well over 3 gigs worth of material. A smaller
download, BasicTeX, is available, requiring a download of roughly 110 megs. In the past, we provided a package named MacTeX-Additions, containing Ghostscript and the GUI apps for users of
BasicTeX. In 2017, we eliminated MacTeX-Additions. Instead, we provide a Ghostscript standalone install package, and provide links to the web pages supporting the GUI apps in MacTeX.

Both MacTeX and BasicTeX install ``TeX Distribution Data Structures'' in /Library/TeX/Distributions containing links to various parts of the distribution. This data is used by
TeX Live Utility, by Ghostscript, and by others. Data structures from other distributions remain untouched. Our philosophy is that each distribution should control its own data.

Ghostscript 9.23

Ghostscript-9.23 was extensively customized to support typesetting in the Far East. We were initially contacted by Munehiro Yamamoto about revisions for Japan. Then work was done by Kuroki Yusuke, Bruno Voisin, and Norbert Preining to perfect the configuration.

Ghostscript installs resources in /usr/local/share/ghostscript/9.23/Resource. By adding material to this location, Ghostscript can be enhanced without recompiling. Ghostscript comes with the "base 35" fonts required for Postscript, and this is enough for standard TeX applications like converting postscript files to pdf files, or converting eps illustrations to png illustrations.
But sometimes, Ghostscript requires access to additional fonts. Two years ago, Bruno Voisin
extended our Ghostscript package to give it access to many pfb font files in TeX Live.

In China, Japan, and Korea, more much extensive knowledge of CJK fonts is often required, depending on the typesetting engine used. Yusuke, Voisin, and Preining provide this knowledge for Japanese. Preliminary work has also been done for Chinese and Korean. In addition, Preining wrote a script which can search a user's machine for other fonts and add appropriate configuration files to Ghostscript. All of this is described in more detail in a document MacTeX installs in
/Applications/TeX, and in a READ ME file for users in Japan by Yusuke Terada, also installed
in /Applications/TeX.

TeX Live 2018

About TeX Live

MacTeX installs a completely unmodified copy of the full TeX Live 2018 distribution. This is exactly the same distribution that runs on OS X, Windows, GNU/Linux, various BSD Unix systems, and other systems.

Notable TeX Live changes

Two changes may be immediately noticeable. The first is that the default encoding for input sources to LaTeX has changed from ISO Latin 9 to UTF-8 Unicode. Standard ASCII files satisfy both encoding rules and thus are accepted as usual. Latin 9 is an encoding standard that adds to ASCII various accents, umlauts, and special characters like upside down question marks used in Western Europe. From 2018 on, such input files require a LaTeX header line

\usepackage[latin9]{inputenc}

UTF-8 is an encoding standard for full unicode, which can simultaneously encode most scripts used across the world: Roman, Arabic, Chinese, Hebrew, Hieroglyphics, Japanese, etc. Until now, Latex sources using this encoding required the header line

\usepackage[utf8]{inputenc}

but this line is now optional because UTF-8 is the default.

The second issue may or may not be noticeable. Synctex is an addition to TeX by Jérôme Laurens; when it is activated, LaTeX and other typesetting engines output an extra ".synctex" file during typesetting, which is then used by front ends to move rapidly from text in the source to the corresponding typeset text, and visa versa. The Synctex package includes parser code by Laurens that front ends can use to implement this syncing.

In 2017, SyncTeX was rewritten by Laurens, and then the parser code was substantially rewritten, changing some of the function calls and data structures. This parser code was released in July, 2017, about a month after the release of TeX Live 2017. The new parser code was almost immediately adopted by TeXShop, but perhaps not by other front ends, particularly those for systems other than the Macintosh.

This parser code is now in TeX Live 2018. During the pretest period, it is causing some concern for front end authors, although the scope of that concern is unclear. TeXShop works fine with the 2018 sync code, and will soon contain additional changes made by Laurens later in 2017-2018; these changes have already been tested locally and work fine. A few front ends could experience short-lived problems at release time.

Older TeX Live Changes

We'd like to call attention to three changes in TeX Live 2010 which remain important today:

pdf(La)TeX now automatically converts a requested Encapsulated PostScript (EPS) file
to PDF when PDF is being output. The default options are intended to eliminate any
chance of hand-created PDF files being overwritten, but you can also prevent the conversion by putting \newcommand{\DoNotLoadEpstopdf}{} (or \def...) before the \documentclass declaration. Conversion also does not occur if the pst-pdf package is used. For more details, see the epstopdf package documentation (http://ctan.org/pkg/epstopdf-pkg [ctan.org]).

A related change is that execution of a very few external commands from TeX, via
the \write18 feature, is now enabled by default. These commands are repstopdf,
makeindex, kpsewhich, bibtex, and bibtex8; the list is defined in texmf.cnf.
Environments which must disallow all such external commands can deselect this option after installation by running
tlmgr conf texmf shell_escape 0.

Since 2010, the default version for PDF output is 1.5, enabling more compression.
This applies to all the TeX engines when used to produce PDF and to dvipdfmx. Loading
the pdf14 LaTeX package changes back to PDF 1.4, or set \pdfminorversion=4.